☣️ UN 3357 • CLASS 3
UN 3357 — Nitroglycerin mixture, desensitized, liquid, n.o.s., with not more than 30% nitroglycerin
Placard: Flammable. ERG Guide 113. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ Verification required:
Broad or variable material category; verify exact product, SDS and shipping papers.
⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
UN 3357 At a Glance
UN 3357 (Nitroglycerin mixture, desensitized, liquid, with not more than 30%…) is listed as DOT Class 3 Flammable and is assigned to ERG Guide 113. Use this page to review placard data, common hazards, PPE notes, isolation context, first actions, and related UN numbers.
UN 3357 covers liquid nitroglycerin mixtures desensitized with solvent or diluent. The liquid form may still leave dangerous dried residue.
Hazard overview: The mixture is flammable and may become much more sensitive if the desensitizer separates, evaporates or dries. Dried residue must be treated as explosive.
Response guidance: Isolate the area, prevent ignition, avoid impact or friction and keep unnecessary personnel away. Use compatible agents and avoid high-pressure streams that spread liquid.
Advertisement
UN 3357 Quick Details
UN 3357
Product name: Nitroglycerin mixture, desensitized, liquid, n.o.s., with not more than 30% nitroglycerin
DOT Class: 3
Placard type: Flammable
ERG Guide: 113 (check current ERG)
Initial isolation: ERG 113: isolate spill 50m all directions; evacuate 800m downwind if large spill; treat any dried material as high explosive
Common Hazards of UN 3357
- Flammable/combustible material.
- May be ignited by heat, sparks or flames.
- DRIED OUT material may explode if exposed to heat, flame, friction or shock; treat dried material as an explosive.
- Keep material wet with water or treat as an explosive (GUIDE 112).
- Runoff to sewer may create fire or explosion hazard.
- Some are toxic and may be fatal if inhaled, ingested or absorbed through skin.
- Contact may cause burns to skin and eyes.
- Fire may produce irritating, corrosive and/or toxic gases.
Chemical Identity & Physical Properties
UN 3357 is typically an oily colorless to pale yellow liquid diluted with a desensitizing solvent; dried residue is the critical concern.
| Also known as | Desensitized nitroglycerinNG solutionNitroglycerin liquid mixtureGlyceryl trinitrate mixtureDesensitized dynamite oil |
| Appearance | Oily colorless to pale yellow liquid, typically diluted with a desensitizing solvent. Low volatility but dangerous dried residue may remain. |
| Flash Point | Approximately 13C (55F) for typical desensitized mixtures |
| Boiling Point | 160C (320F) with decomposition - rarely reaches boiling point as it decomposes |
| Vapor Density | Not applicable (low volatility liquid) |
| Water Reactivity | No significant reaction with water, but desensitizer may separate allowing nitroglycerin to concentrate |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 3357
Extinguishing Media
Alcohol-resistant foam, CO2, dry chemical - avoid high-pressure water streams that may spread liquid
PPE Requirements
⚠️ Level B minimum with full face SCBA; nitrile or butyl rubber gloves; avoid any impact or friction to dried residue
Use Level B with SCBA, chemical-resistant gloves and full protective clothing. Treat dried or heated material as explosive.
Isolation & Evacuation
ERG 113: isolate spill 50m all directions; evacuate 800m downwind if large spill; treat any dried material as high explosive
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 113).
First Actions for a UN 3357 Incident
- CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area immediately for at least 100 meters (330 feet) in all directions.
- Consider initial evacuation for 500 meters (1/3 mile) in all directions.
Advertisement
📋 Copy & Share Field Card
UN 3357 — Nitroglycerin mixture, desensitized, liqHAZMAT RADIO NOTE — UN 3357
Product: Nitroglycerin mixture, desensitized, liquid, n.o.s., with not more than 30% nitroglycerin
Class 3 / Flammable / ERG 113
PPE: Level B minimum with full face SCBA; nitrile or butyl rubber gloves; avoid any impact or friction to dried residue
ISOLATION: ERG 113: isolate spill 50m all directions; evacuate 800m downwind if large spill; treat any dried material as high explosive
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 3357 — Nitroglycerin mixture, desensitized, liquid, n.o.s., with not more than 30% nitroglycerin
Class: 3 | Placard: Flammable | ERG Guide: 113
Appearance: Oily colorless to pale yellow liquid, typically diluted with a desensitizing solvent. Low volatility but dangerous dried residue may remain.
Water Reactivity: No significant reaction with water, but desensitizer may separate allowing nitroglycerin to concentrate
Extinguishing: Alcohol-resistant foam, CO2, dry chemical - avoid high-pressure water streams that may spread liquid
PPE: Level B minimum with full face SCBA; nitrile or butyl rubber gloves; avoid any impact or friction to dried residue
Isolation: ERG 113: isolate spill 50m all directions; evacuate 800m downwind if large spill; treat any dried material as high explosive
— Key Hazards —
• Flammable/combustible material.
• May be ignited by heat, sparks or flames.
• DRIED OUT material may explode if exposed to heat, flame, friction or shock; treat dried material as an explosive.
— First Actions —
• CALL 911. Then call the emergency response telephone number on the shipping paper, if available.
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
SOURCE: allfirefighter.com/hazmat/un/nitroglycerin-mixture-desensitized-liquid-un-3357 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN3357 Nitroglycerin mixture, desensitized, liquid, n.o.s., with not more than 30% nitroglycerin Cls3 ERG113 | allfirefighter.com/hazmat/un/nitroglycerin-mixture-desensitized-liquid-un-3357SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/nitroglycerin-mixture-desensitized-liquid-un-3357
Advertisement
Frequently Asked Questions about UN 3357
UN 3357 is a desensitized liquid nitroglycerin mixture with not more than 30% nitroglycerin.
Yes. It is a flammable liquid entry.
Drying can reduce desensitization and make residue shock- or friction-sensitive.
Avoid heat, sparks, friction, impact and high-pressure water streams.
SCBA with Level B protection and chemical-resistant gloves is recommended.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.